Audio amplifier



FIG. 1 is a perspective view of an audio amplifier;

FIG. 2 is a front elevational view of the audio amplifier;

FIG. 3 is a rear elevational view of the audio amplifier;

FIG. 4 is a top plan view of the audio amplifier;

FIG. 5 is a bottom plan view of the audio amplifier;

FIG. 6 is a right side elevational view of the audio amplifier;

FIG. 7 is a left side elevational view of the audio amplifier; and,

FIG. 8 is a perspective view of the audio amplifier shown in a state of use.

Portions of the audio amplifier shown in evenly-spaced broken lines form no part of the claimed design.

The dot-dash broken lines define a boundary of the claimed design and forms no part of the claimed design.

The dot-dot-dash line showing of the stands in FIG. 8 depicts environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for an audio amplifier, as shown and described. 